1. Field of the Invention
The present invention relates to a method of repairing a liquid crystal display panel, and more particularly to a method of repairing a ferroelectric liquid crystal display panel, that repairs a short circuit occurred between upper and lower electrodes owing to inclusion of a foreign matter in a cell.
2. Related Background Art
Since publication of twisted-nematic liquid crystals (TN liquid crystals) in "Applied Physics Letters", Vol. 18, No. 4, pp. 127-128, by Shadt and W. Helfrich in 1971, liquid crystal display panels have made rapid progress, but recent trend in development of goods is shifting from original numerical display panels using segment electrodes to character display panels using a dot matrix. Particularly in recent years demanded is commericialization of liquid crystal display panels having a picture element of a large capacity and capable of answering for the display screens of word processors or personal computers and the display screens of televisions.
However, in multiplexing drive of the above TN liquid crystals, duty ratio decreases in the proportion of 1/N with increase in the number (N) of scanning lines, and hence there has been a limit in increasing the number of scanning lines. In the case of liquid crystal display panels of the type that picture elements formed at the sites at which scanning lines and data lines cross are controlled for each picture element, thin film transistors in the number corresponding to the number of picture elements are required to be formed on a liquid crystal display panel substrate, but a technically very difficult problem has been involved in forming this thin film transistors over a large area.
As a liquid crystal display panel that can solve these problems, proposed was the surface stability ferroelectric liquid crystal device published in "Applied Physics Letters", Vol. 36, No. 11, pp. 899-901, by N. Clark and S. T. Lagerwall in 1980. This ferroelectric liquid crystal device produces two stably aligned states by which a contrast can be discriminated according the direction of an electric field. This has made it necessary to set the cell thickness to be small enough to bring the spiral structure inherent in a chiral smectic liquid crystal to disappear, which thickness is exemplified by 0.5 .mu.m to 2 .mu.m in approximation.
For this reason, there have been the problem that a short circuit may occur between upper and lower electrodes simply by inclusion of a minute foreign matter in the inside of a cell of the above ferroelectric liquid crystals. In particular, when the ferroelectric liquid crystal cell wired as the upper and lower electrodes with matrix electrodes (a scanning electrode and a signal electrode) for the multiplexing drive, any short-circuited part present at the site at which scanning lines and data lines cross may be identified by a viewer as a line defect (non-switching line) having a shape of a cross formed by the scanning line and signal line at the short-circuited part, resulting in a lowering of display quality.